KR100495757B1 - Master cylinder - Google Patents

Abstract

An object of the present invention is to provide a master cylinder which can shorten the pedal stroke and reduce the discomfort in the pedal filling caused when the hydraulic pressure in the large diameter pressurization chamber is released.

By providing the control valve 86 which can push the hydraulic pressure of the large diameter pressurization chamber 56 to the reservoir side 12 so that the hydraulic pressure of the small diameter hydraulic chamber 49 may be gradually lowered, the stepped piston ( The check opening / closing part 61 is opened by the volume reduction of the large diameter pressurization chamber 56 by the sliding movement to the small diameter hydraulic chamber side 49 of 16), and the small diameter hydraulic chamber side ( 49) The liquid is supplied to the large diameter pressurizing chamber 56 by supplying liquid, that is, the first fill, and the control valve 86 causes the hydraulic pressure of the large diameter pressurizing chamber 56 to increase. As the hydraulic pressure rises, it is pushed out to the reservoir 12 so as to decrease gradually.

Description

Master Cylinder {MASTER CYLINDER}

The present invention relates to a master cylinder for supplying brake fluid to a brake device of an automobile.

As a conventional master cylinder, brake fluid for brake devices such as disc brakes and drum brakes, as described in the microfilm of Japanese Utility Model Registration Application No. 55-152602 (Utility Model Publication No. 57-73248). By supplying a large amount of brake fluid at the initial stage of operation, the so-called first fill is used to replenish the amount of invalid liquid at the beginning of the stroke, and as a result, the pedal stroke can be shortened (first fill master cylinder).

The first fill master cylinder is a stepped cylinder having a large diameter cylinder portion and a small diameter cylinder portion, and is inserted into the large diameter cylinder portion of the stepped cylinder so as to be slidable. A stepped piston having a large diameter piston portion and a small diameter piston portion slidably inserted into the small diameter cylinder portion, and the inside of the stepped cylinder to a large diameter pressurizing chamber on the large diameter piston portion side and a small diameter hydraulic chamber on the small diameter piston portion side. At the same time, a cup seal (reverse opening / closing portion) is provided which allows only the flow of the brake fluid from the large diameter pressure chamber side to the small diameter hydraulic chamber side.

Then, when the stepped piston slides toward the small-diameter hydraulic chamber by the input of the brake pedal, the check opening / closing part is opened by opening the check opening part by the volume reduction of the large-diameter pressurized chamber by the sliding movement of the stepped piston to the small-diameter hydraulic chamber side. The first fill is performed by supplying a liquid from the diameter pressurization chamber side to the small diameter hydraulic chamber side.

Moreover, this first fill master cylinder is provided with a relief valve which pushes brake fluid from the large diameter pressurizing chamber to the reservoir when the internal pressure of the large diameter pressurizing chamber reaches a predetermined value or more, and the relief valve has a large diameter pressurizing chamber. A cutout portion is provided so that the nozzle always communicates with the reservoir, and the liquid is supplied from the reservoir to the large diameter pressurization chamber by an extremely small diameter communication path by the cutout portion.

By the way, in the said master cylinder, since the notch was provided, the liquid of the large diameter pressurization chamber flowed into the reservoir at the time of low pressure rising, and there existed a problem that a sufficient first fill could not be performed.

In the master cylinder, when the internal pressure of the large diameter pressurization chamber is equal to or greater than a preset value, the relief valve is opened to push the brake fluid from the large diameter pressurization chamber to the reservoir at once. When the pressure of the large diameter pressurization chamber rises to a predetermined pressure during the operation of pressing down at a relatively high speed, the hydraulic pressure of the large diameter pressurization chamber is released at once by the opening operation of the relief valve. The pedal stroke was elongated without being accompanied by the pedal reaction force, and moved to the small-diameter hydraulic chamber side, causing a feeling of discomfort on the pedal peeling type such that the vehicle speed was reduced only with a feeling of lightly stepping off.

In addition, in order to improve the performance of the first fill, the conventional first fill type master cylinder is closed by a sliding movement of the stepped piston toward the small diameter hydraulic chamber side, and the large diameter pressurization chamber side blocking portion which blocks communication between the large diameter pressurization chamber and the reservoir, Some of the stepped pistons are closed by sliding toward the small-diameter hydraulic chamber side and are provided with a small-diameter hydraulic chamber side shut-off section for blocking communication between the large-diameter pressure chamber and the small-diameter hydraulic chamber. In order to improve the performance of the first fill in such a master cylinder, it is necessary to shorten the invalid stroke of the stepped piston until the small diameter hydraulic chamber side blocking portion and the large diameter pressurizing chamber side blocking portion are closed.

However, if the invalid stroke is simply set short, the flow path cross-sectional area of the small diameter hydraulic chamber side blocking portion and the large diameter pressurizing chamber side blocking portion is narrowed. Thus, when the flow path cross section is narrowed, when used in combination with a traction control device, a sufficient flow rate when the traction control device forcibly draws brake fluid from the reservoir through the master cylinder to operate the brake device. That is, there is a problem that the brake fluid cannot be flowed by high flow.

On the other hand, a traction control device is a wheel from a reservoir via a master cylinder, for example, when a driver excessively operates an accelerator on a slippery road surface when wheel brakes are not generated, and wheelspin is formed on a driving wheel of a car. By braking the driving wheels by forcibly supplying brake fluid to a brake device such as a cylinder, the wheel spin is reduced. The master cylinder used in combination with the traction control unit can obtain the ability (high flow performance) to allow the brake fluid to flow to the traction control unit at high flow in the initial state.

For this reason, the present applicant considered applying the structure of Japanese Patent Application No. Hei 10-294502 for which it applied previously to the small diameter hydraulic chamber side break part and the large diameter pressurization chamber side break part. This structure is a structure which closes the port opened to the outer peripheral part of a piston with a cup seal by sliding a piston, and forms the control taper surface which becomes small diameter in front of the opening part of the port of the outer peripheral part of a piston at the back side, Even if the entire cup seal does not completely exceed the pot during the sliding movement, the rear end of the cup seal rises through the control taper surface to increase the surface pressure and close the port, which responds to high flow, The invalid stroke can be shortened.

However, when the above structure is applied to the small-diameter hydraulic chamber breaker and the large-diameter pressure chamber-side breaker, control tapered surfaces must be formed on both sides, and the positional accuracy of both ports must be strictly managed. There was a problem that the cost would increase.

This invention is made | formed in view of the said situation, The objective is to provide the master cylinder which can ensure the performance of a first peel, and can reduce the discomfort on pedal peeling which arises when releasing the hydraulic pressure of a large diameter pressurization chamber. .

Further, another object of the present invention is to provide a master cylinder which can shorten the pedal stroke and reduce the cost while satisfying the high flow performance required when the traction control device is combined.

In order to achieve the above object, the master cylinder of the present invention includes a stepped cylinder having a large diameter cylinder portion and a small diameter cylinder portion, and a large diameter piston portion slidably inserted into the large diameter cylinder portion of the stepped cylinder. And a stepped piston having a small diameter piston portion slidably inserted into the small diameter cylinder portion, and the inside of the stepped cylinder is divided into a large diameter pressurizing chamber on the large diameter piston portion side and a small diameter hydraulic chamber on the small diameter piston portion side. And a check opening / closing portion for allowing only the flow of the brake fluid from the large diameter pressure chamber side to the small diameter hydraulic chamber side, and the sliding of the stepped piston toward the small diameter hydraulic chamber side of the large diameter pressure chamber. The check opening / closing part is opened by volume reduction, and from the large diameter pressurization chamber side. Group small-diameter as a master cylinder that supplies the liquid to the liquid pressure chamber side, characterized in that it includes a control valve for the hydraulic pressure of the small-diameter pressurization chamber gradually decreases according to the increase of the hydraulic pressure fluid pressure chamber diameter.

The control valve has a valve piston and a valve spring for urging the valve piston in the valve cylinder, and the valve piston is generated by the driving force generated by the hydraulic pressure of the small diameter hydraulic chamber and the hydraulic pressure of the large diameter pressure chamber. When the force which added the thrust force exceeds the pressing force by the said valve spring, it can be set as the structure which reduces the hydraulic pressure of the said large diameter pressurization chamber.

In addition, the master cylinder is provided with a reservoir for storing brake fluid, and the control valve is provided with at least two ring seals between the valve cylinder and the valve piston so as to partition the inside of the valve cylinder, and between the ring seals. The formed chamber and the small diameter hydraulic chamber communicate with each other, the valve spring is installed at one end side of the valve piston, and a relief chamber communicating with the reservoir and the large diameter pressurization chamber is installed at the other end side of the valve piston. The relief chamber and the large diameter pressurization chamber can be configured to have an on-off valve mechanism for intercepting and cutting off. The at least two ring seals may be provided on the valve piston, and the diameter of the ring seals provided on the valve spring side may be larger than the diameter of the ring seals provided on the relief chamber side.

Thus, since it has a control valve which can push the hydraulic pressure of a large diameter pressurization chamber to a reservoir side so that it may fall gradually with the increase of the hydraulic pressure of a small diameter hydraulic chamber, in order to slide a stepped piston to the small diameter hydraulic chamber side. When the large diameter pressurization chamber decreases in volume, the check opening is opened and the liquid is supplied from the large pressurization chamber side to the small diameter pressurizing chamber side. The hydraulic pressure of the pressure chamber is pushed out to the reservoir so as to gradually decrease as the pressure of the small diameter hydraulic chamber increases. Therefore, the pedal stroke can be shortened by the effect of the first peel, and when the hydraulic pressure of the large diameter pressurizing chamber is released, the hydraulic pressure of the large diameter pressurizing chamber is gradually lowered without dropping.

Moreover, since at least two ring seals are provided in the valve piston, and the diameter of the ring seal provided on the valve spring side is larger than the diameter of the ring seal provided on the relief chamber side, it is formed between the ring seals. The valve piston can be pressed by the hydraulic pressure acting in the chamber, thereby driving the on-off valve mechanism.

In addition, the valve cylinder is divided into three chambers, a chamber formed between the relief chamber and the ring seal, and a damper chamber in which the valve spring is stored, by two ring seals, and one end side of the valve piston is opened to the relief chamber. At the same time, it is possible to have a configuration in which a throttle passage in which the other end side is opened to the damper chamber is formed.

As a result, the damper chamber and the relief chamber communicate with each other through the throttle passage, so that the valve piston of the on-off valve mechanism is minutely driven at a high speed when the hydraulic pressure in the large-diameter pressure chamber is pushed down to the reservoir side in order to gradually decrease the hydraulic pressure in the small-diameter hydraulic chamber. When vibrating, the volume of the damper chamber repeats a slight increase and decrease. As a result, the brake fluid flows between the damper chamber and the relief chamber through the throttle passage, and the throttle passage becomes a liquid flow resistance, thereby providing a damper effect. .

In addition, the master cylinder is closed by the reservoir for storing the brake fluid and the stepped piston by sliding to the small diameter hydraulic chamber side, the large diameter pressurization chamber side blocking portion to block the communication between the large diameter pressurizing chamber and the reservoir. And a small diameter hydraulic chamber side blocking part for closing the stepped piston by sliding toward the small diameter hydraulic chamber side to block communication between the large diameter pressure chamber and the small diameter hydraulic chamber, and the small diameter hydraulic chamber side The invalid stroke of the stepped piston until the breaking portion is closed can be configured to be longer than the invalid stroke of the stepped piston until the large diameter pressurization chamber side breaking portion is closed.

In addition, the master cylinder of the present invention includes a stepped cylinder having a large diameter cylinder portion and a small diameter cylinder portion, a large diameter piston portion and a small diameter cylinder portion slidably inserted into the large diameter cylinder portion of the stepped cylinder. A stepped piston having a small diameter piston portion slidably inserted therein; the stepped cylinder is divided into a large diameter pressurizing chamber on the large diameter piston part side and a small diameter hydraulic chamber on the small diameter piston part side, and the large diameter pressurizing pressure A check opening / closing part allowing only the flow of brake fluid from the actual side to the small diameter hydraulic chamber side, and the stepped piston is closed by sliding toward the small diameter hydraulic chamber side to block communication between the large diameter pressurizing chamber and the reservoir. The diameter pressurization chamber side blocking part and the said stepped piston are the said small diameter hydraulic chamber side And a small diameter hydraulic chamber side blocking portion for closing the sliding between the large diameter pressurizing chamber and the small diameter hydraulic chamber to prevent communication between the large diameter pressurizing chamber and the small diameter hydraulic chamber side. A master cylinder which opens the check opening / closing part by volume reduction of the diameter pressurizing chamber to supply liquid from the large diameter pressurizing chamber side to the small diameter hydraulic chamber side, wherein the stage until the small diameter hydraulic chamber side blocking part becomes closed. The invalid stroke of the differential piston is elongated with respect to the invalid stroke of the stepped piston until the large diameter pressurization chamber side breaker is closed.

In such a configuration, when the liquid is supplied from the large diameter pressurizing chamber to the small diameter hydraulic chamber, the large diameter pressurizing chamber side blocking part having the short invalid stroke is closed even if the small diameter hydraulic chamber blocking part having the long invalid stroke is not closed. If there is, the flow of brake fluid caused by the volume reduction of the large diameter pressurization chamber due to the sliding of the stepped piston to the small diameter hydraulic chamber side passes from the large diameter pressurization chamber side to the small diameter hydraulic chamber side. In this case, since the liquid flows from the large diameter pressurization chamber side through the check opening / closing part to the small diameter hydraulic chamber side, the first peel performance is not lowered.

Moreover, since liquid supply from the large diameter pressurization chamber at the initial stage of operation to the small diameter hydraulic chamber can be performed without going through the check opening / closing portion, liquid flow resistance does not occur, and the first fill performance is further improved.

Thus, since the invalid stroke of the stepped piston until the small diameter hydraulic chamber side blocking part is closed is long relative to the invalid stroke of the stepped piston until the large diameter pressurizing chamber side blocking part is closed, As for the master cylinder, the short stroke of the invalid stroke for the early realization of the first fill performance may be managed only by the axial positioning accuracy of the large diameter pressurization chamber breaker, and the axial position accuracy with respect to the small diameter hydraulic chamber breaker. There is no need to strictly manage.

For this reason, the large diameter pressurization chamber side blocking part responds to high flow, and the invalid stroke is short, and it is the blocking structure corresponding to the first fill, and the small diameter hydraulic chamber side blocking part is the low cost type breaking structure with long invalid stroke which responds to high flow. You can do

The master cylinder of 1st Embodiment of this invention is demonstrated with reference to FIGS.

FIG. 1 shows a master cylinder of the first embodiment, and in FIG. 1, reference numeral 11 denotes a master cylinder body that generates brake hydraulic pressure in response to an input of a brake pedal introduced through a booster (not shown). 12 denotes a reservoir attached to an upper portion of the master cylinder body 11 to store brake fluid supplied and discharged to the master cylinder body 11.

The master cylinder main body 11 has a substantially bottomed cylindrical stepped cylinder 15 along the transverse direction and a primary that is slidably fitted to the opening side (right side in the drawing) of the stepped cylinder 15. A piston (stepped piston) 16 and a secondary piston 17 fitted to slide freely to the bottom 15a side (left side in the drawing) than the primary piston 16 of the stepped cylinder 15 have.

The stepped cylinder 15 includes a bottomed cylindrical first member 21 having a bottom portion 15a of the stepped cylinder 15 and a hole portion 20 formed along the horizontal direction, and The substantially cylindrical second member 22, the third member 23, the fourth member 24, and the first, which are sequentially inserted into the hole 20 of the first member 21 from the bottom 15a side. 5th member 25 and the 6th member 26 provided so that the said 5th member 25 may be covered to the opposite side with respect to the bottom part 15a of the 5th member 25, and this 6th member 26 The seventh member which is provided on the opposite side to the bottom portion 15a of the upper surface and is screwed to the first member 21 to hold the second member 22 to the sixth member 26 in the first member 21 ( 27).

The secondary piston 17 is fitted inside the second member 22 so as to be slidable. The secondary piston 17 has a cylindrical shape with a bottom having a hole portion 30 formed at one end thereof, and the hole portion 30 is made to face the bottom portion 15a of the first member 21. 2 members 22 are fitted.

Here, the part enclosed by the bottom part 15a side of the 1st member 21 and the bottom part 15a side of the secondary piston 17, ie, the hole part 30 side, is made into the secondary side small diameter hydraulic chamber 32. As shown in FIG. It is becoming. In addition, 113 is a secondary side discharge hole provided in the 1st member 21, and the said secondary side discharge hole 113 does not show a brake fluid when the hydraulic pressure generate | occur | produced in the said secondary side small diameter hydraulic chamber 32 It is directed toward the brake unit or the traction control unit.

One end side of the second member 22 is opened to the inner circumferential surface of the second member 22 in the radial direction, and the other end side of the second member 22 is connected to the reservoir 33 through the flow path 33 of the first member 21. The port 34 is always in communication with 12, and the secondary piston 17 is provided with a relief port 35 capable of communicating the port 34 with the secondary-side hydraulic cylinder 32. .

Between the 2nd member 22 and the 1st member 21, the cup seal 36 which can interrupt communication with the secondary side small diameter hydraulic chamber 32 and the port 34 is provided. The cup seal 36 interrupts the communication when the hydraulic pressure of the secondary side small diameter hydraulic chamber 32 is greater than or equal to the hydraulic pressure on the reservoir 12 side, and the hydraulic pressure of the secondary side small diameter hydraulic chamber 32 is maintained in the reservoir. If it is lower than the liquid pressure on the (12) side, these are connected to enable liquid replenishment.

An initial state (hereinafter, at this time) with no input from the brake pedal side (right side in the drawing) not shown between the hole portion 30 of the secondary piston 17 and the bottom portion 15a of the first member 21. The position of each part is called the initial position), and the secondary piston spring 38 which determines these space | intervals is provided. When in this initial position, the secondary piston 17 communicates the relief port 35 to the port 34. As a result, the secondary side small diameter hydraulic chamber 32 communicates with the reservoir 12.

When the secondary piston 17 moves to the bottom part 15a side of the 1st member 21 in this state, in the state in which the hydraulic pressure of the secondary side small diameter hydraulic chamber 32 is more than the hydraulic pressure of the reservoir 12 side, the said secondary piston 17, the relief port 35 is closed by the cup seal 36, and communication with the port 34 is interrupted. As a result, communication between the secondary side small diameter hydraulic chamber 32 and the reservoir 12 is lost. By this, the secondary piston 17 also moves to the bottom 15a side, whereby the brake device and the traction control device not shown through the secondary side discharge hole 113 from the secondary side small diameter hydraulic chamber 32. Supply brake liquid to

Here, the secondary side block part in which the secondary piston 17 and the cup seal 36 including the relief port 35 are closed by sliding to the secondary side small diameter hydraulic chamber 32 side of the secondary piston 17 is here. It becomes (200).

The fourth member 24 is a small diameter cylinder portion that is opposite to the small diameter cylinder portion 40 on the bottom portion 15a side of the second member 21 and the bottom portion 15a of the first member 21. It has a stepped shape having a larger diameter cylinder portion 41 of larger diameter than 40, and the primary piston 16 is fitted inside the small diameter cylinder portion 40 so as to be slidable. The large diameter cylinder part 41 is formed with the some axial groove 41a at intervals in the circumferential direction.

The primary piston 16 is formed at one end thereof with a hole portion 43 arranged opposite to the secondary piston 17 and at the same time with a hole portion 44 into which a rod of a booster (not shown) is inserted. A small diameter piston portion 46 inserted slidably into the small diameter cylinder portion 40 of the fourth member 24 and a large diameter cylinder portion 41 slidably inserted into the fourth member 24. It has a large diameter piston part 47 which becomes. This large diameter piston part 47 is also inserted in the 5th member 25 so that sliding is possible.

The side opposite to the bottom 15a of the secondary piston 17 and the small diameter piston portion 46 side of the primary piston 16, that is, the portion surrounded by the hole 43 side and the third member 23 The primary side small diameter hydraulic chamber (small diameter hydraulic chamber) 49 is provided. In addition, 114 is a primary side discharge hole provided in the 1st member 21, This primary side discharge hole 114 is a brake fluid when a hydraulic pressure generate | occur | produced in the said primary side small diameter hydraulic chamber 49, It feeds toward a wheel cylinder or traction control device (not shown).

Here, the third member 23 is provided with a small diameter hydraulic chamber communication flow path 51 which is always in communication with the primary side small diameter hydraulic chamber 49 through the hole 50 between the first member 21. It is.

Between the second member 22, the third member 23, and the secondary piston 17, a cup seal 53 for blocking communication between the primary side small diameter hydraulic chamber 49, the flow path 33, and the port 34. ) Is installed.

Moreover, the small diameter hydraulic chamber communication flow path 51, the flow path 33, and the port are disposed between the bottom portion 15a side and the first member 21 than the small diameter hydraulic chamber communication flow path 51 of the third member 23. An O-ring 54 is provided which always blocks communication of 34.

The part enclosed by the large diameter cylinder part 41 side of the primary piston 16 and the 4th member 24 becomes the large diameter pressurization chamber 56 by the large diameter piston part 47 side.

The fourth member 24 is provided with a port 57 whose one end side is open to the inner circumferential surface in the radial direction of the small diameter cylinder portion 40 and the other end side is always in communication with the large diameter pressurization chamber 56. The small diameter piston portion 46 of the head piston 16 is provided with a relief port 58 capable of communicating the port 57 and the hole portion 43, that is, the primary side small diameter hydraulic chamber 49. have. In addition, the port 57 is always in communication with the pressure chamber communication flow path 59 between the third member 23 and the fourth member 24.

Between the 3rd member 23, the 4th member 24, and the small diameter piston part 46 of the primary piston 16, the side of the primary side small diameter hydraulic chamber 49 and the large diameter pressurization chamber 56 is provided. The cup seal (reverse opening and closing part) 61 which can block communication is provided. This cup seal 61 cuts off the communication when the hydraulic pressure of the primary side small diameter hydraulic chamber 49 is equal to or larger than the hydraulic pressure of the large diameter pressurizing chamber 56, and on the contrary, the hydraulic pressure of the large diameter pressurizing chamber 56 When it is higher than the hydraulic pressure of this primary side small diameter hydraulic chamber 49, these can be communicated. In other words, the cup seal 61 has a small diameter hydraulic pressure at the primary side from the large diameter pressurizing chamber 56 and the small diameter piston portion 46 on the large diameter piston portion 47 side in the stepped cylinder 15. It divides into the chamber 49, and allows only the flow of brake fluid from the large diameter pressurization chamber 56 side to the primary side small diameter hydraulic chamber 49 side.

The small diameter hydraulic chamber communication passage 51 and the large diameter pressurizing chamber 56 are disposed between the first side 21 and the side opposite to the bottom portion 15a than the small diameter hydraulic chamber communication passage 51 of the third member 23. The O-ring 62 which always interrupts communication at the c) side is provided.

Between the secondary piston 17 and the primary piston 16, there is a primary initial positioning mechanism 64 for determining their spacing in the initial state without input from the brake pedal side (right side in Fig. 1) (not shown). It is installed. The primary initial positioning mechanism 64 includes a contact member 65 in contact with the secondary piston 17, and a shaft member 66 fixed to the contact member 65 to extend toward the primary piston 16. The contact member 67 and the contact members 65 and 67 which are in contact with the bottom of the hole 43 of the primary piston 16 while keeping the shaft member 66 movable in a predetermined range, It has the primary piston spring 68 which presses in an opposite direction.

When the primary initial positioning mechanism 64 positions the contact members 65 and 67 to the furthest position defined by the shaft member 66 by the pressing force of the primary piston spring 68, the primary piston 16 is arrange | positioned at an initial position, at this time, the relief port 58 is made to communicate with the port 57, and the primary side small diameter hydraulic chamber 49 is connected to the large diameter pressurization chamber 56 at this time. .

When it moves to the bottom part 15a side in an initial state, when the hydraulic pressure of the primary side small diameter hydraulic chamber 49 is more than the hydraulic pressure of the large diameter pressurization chamber 56, the primary piston 16 will replace the relief port 58 ) Is blocked by the cup seal 61 to block communication with the port 57, and communication through the relief port 58 on the primary side small diameter hydraulic chamber 49 and the large diameter pressurizing chamber 56 side is performed. In this state, when it moves further to the bottom part 15a side, it brakes from the primary side small diameter hydraulic chamber 49 to the brake apparatus and traction control apparatus which are not shown through the primary side discharge hole 114. FIG. Supply the liquid. In addition, even when the relief port 58 is closed, when the hydraulic pressure of the large diameter pressurization chamber 56 is more than the hydraulic pressure of the primary side small diameter hydraulic chamber 49, the large diameter pressurization chamber 56 is provided through the cup seal 61. Of the brake fluid flows into the primary-side small diameter hydraulic chamber 49.

Here, the small diameter piston part 46 including the relief port 58 and the cup seal 61 are closed by sliding to the primary side small diameter hydraulic chamber 49 side of the primary piston 16, A small diameter hydraulic chamber side blocking part 201 for interrupting communication between the large diameter pressurizing chamber 56 and the primary side small diameter hydraulic chamber 49 is used.

The 4th member 24 forms the liquid supply chamber 71 of atmospheric pressure which always communicates with the reservoir 12 through the flow path 70 of the 1st member 21 between the 1st member 21 and the 1st member 21. . The width of the bottom part 15a side and the 1st member 21 of the 4th member 24 of the liquid supply chamber 71 communicates with the large diameter side pressure chamber 56 and the liquid supply chamber 71. As shown in FIG. The O-ring 72 which always blocks is provided.

The fifth member 25 is provided with a port 74 whose one end side is open to the inner circumferential surface in the radial direction and the other end side always communicates with the liquid supply chamber 71. The primary piston 16 has one end. The side is open to the outer circumferential surface in the radial direction of the large diameter piston portion 47 so as to communicate with the port 74, that is, the liquid supply chamber 71, while the other end side has the large diameter piston portion 47 and the small diameter piston portion. The relief port 76 which always communicates with the edge part 75 of the boundary with 46, ie, the large diameter pressurization chamber 56, is formed.

Between the fourth member 24, the fifth member 25, and the large diameter piston portion 47 of the primary piston 16, communication between the large diameter pressurization chamber 56 and the liquid supply chamber 71 can be interrupted. The cup seal 78 is provided. The cup seal 78 blocks these communication when the hydraulic pressure of the large diameter pressurization chamber 56 is equal to or greater than the liquid pressure of the liquid supply chamber 71. On the contrary, the liquid pressure of the liquid supply chamber 71 is the large diameter pressurization chamber. If the pressure is higher than 56, these fluids are communicated to replenish the liquid.

When in the initial position, the primary piston 16 communicates the relief port 76 to the port 74, and the large diameter pressurization chamber 56 to the liquid supply chamber 71. And when the primary piston 16 slides to the bottom part 15a side, ie, the primary side small diameter hydraulic chamber 49 side in an initial state, the hydraulic pressure of the large diameter pressurization chamber 56 side will become a liquid supply chamber. When the hydraulic pressure is greater than or equal to 71, the relief port 76 is blocked by the cup seal 78 so as to block communication with the port 74, and the above-mentioned large diameter pressurization chamber 56 and liquid supply chamber 71 When the communication through the relief port 76 is interrupted, and the slide is made toward the primary side small diameter hydraulic chamber 49, the primary piston 16 has a large diameter piston portion 47 with a large diameter pressure chamber 56. By lowering the volume of the valve), the hydraulic pressure of the large diameter pressurization chamber 56 is increased, and the cup seal 61 provided between the large diameter pressurization chamber 56 and the primary side small diameter hydraulic chamber 49 is opened. The liquid is supplied from the large diameter pressurization chamber 56 side to the primary side small diameter hydraulic chamber 49.

Here, the large diameter piston part 47 and the cup seal 78 including the relief port 76 are closed by sliding to the primary side small diameter hydraulic chamber 49 side of the primary piston 16. The large diameter pressurization chamber side blocking part 202 which interrupts communication with the large diameter pressurization chamber 56 and the liquid supply chamber 71, ie, the reservoir 12, is used.

A cup seal 79 is provided between the fifth member 25, the sixth member 26, and the large diameter piston portion 47 of the primary piston 16, and the first member 21 and the sixth member ( O-ring 80 is provided between the 26.

In addition, the relief ports 35, 58, and 76 are all large in diameter (phi) 2 (mm) in order to suppress liquid flow resistance, and are provided in several places, respectively.

And in this embodiment, until the invalid stroke of the primary piston 16 until the small diameter hydraulic chamber side blocking part 201 is closed, until the large diameter pressurization chamber side blocking part 202 is closed. The primary piston 16 is extended to the invalid stroke, and specifically, the large diameter pressurization chamber side blocking part 202 is made into the block structure which responded to high flow and the reactive stroke respond | corresponds to a short first fill, The small-diameter hydraulic chamber breaker 201 is a low-cost type breaker structure having a long invalid stroke corresponding to high flow.

The small diameter hydraulic chamber side blocking part 201 has comprised the structure shown in FIG. 2, and the large diameter pressure chamber side blocking part 202 has the structure shown in FIG.

Here, although the cup seals 61 and 78 used for the small diameter hydraulic chamber side blocking part 201 and the large diameter pressurization chamber side blocking part 202 differ in size, together with the disk-shaped bottom part 205 in a substantially annular shape, An annular inner lip portion 206 protruding from the inner circumferential side of the bottom portion 205 to one side, and an annular outer lip portion 207 protruding from the outer circumferential side of the bottom portion 205 in the same direction as the inner lip portion 206. The inner lip 206 is slightly inclined so that the diameter of the protruding tip side becomes small in a free state that does not receive external force, and the outer lip 207 is slightly inclined so that the diameter of the protruding tip side becomes large in the free state. . 2 and 3, the cup seals 61, 78 are shown in the free state.

The large diameter pressurization chamber cut-off part 202 is demonstrated.

The large diameter piston portion 47 of the primary piston 16 becomes the small diameter outer diameter portion 210 having a straight shape while the outer peripheral portion at the bottom side 15a side (the left side in FIG. 3), that is, the front side, Although the outer peripheral part on the opposite side with respect to 15a) is a small diameter outer diameter part (210 beams), it becomes a large diameter straight diameter large diameter outer diameter part 211, and these small diameter outer diameter parts 210 and large diameter outer diameter parts 211 The taper outer diameter portion 212 is inclined so as to continue them. Further, since the tip portion at the bottom 15a side is slidably guided to the large diameter cylinder portion 41 of the fourth member 24, the larger diameter than the small diameter outer diameter portion 210, more than the small diameter outer diameter portion 210. Is the outer diameter portion 213 of the tip.

And the said relief port 76 makes the opening part 76a of the small diameter outer diameter part 210 side of the taper outer diameter part 212 the one part of the taper outer diameter part 212 side of the small diameter outer diameter part 210. Opening to some side. And the cup seal 78 is located in the initial position at the outer diameter side of the small diameter outer diameter part 210, and is superimposed on the opening part 76a slightly.

In the large diameter pressurization chamber side blocking part 202, when the primary piston 16 slides from an initial position, the rear end part of the cup seal 78 has a taper outer diameter part on the larger diameter outer diameter part 211 side than the opening 76a ( 212), the cup seal 78 expands in diameter, thereby partially increasing the fastening value for the primary piston 16, i.e., the urge force, and partially peaking between the primary piston 16. The surface pressure is generated to have. As a result, the cup seal 78 interrupts communication between the large diameter pressurization chamber 56 and the liquid supply chamber 71, that is, the reservoir 12, through the relief port 76.

In addition, when the primary piston 16 advances and the rear end of the cup seal 78 is lifted up at the corner of the boundary between the tapered outer diameter portion 212 and the large diameter outer diameter portion 211, the cup seal 78 ) Is in linear contact with the primary piston 16 at each part, thereby placing the peak of the surface pressure at this line contacting portion. As a result, the cup seal 78 continues to block the communication between the large diameter pressurization chamber 56 and the liquid supply chamber 71, that is, the reservoir 12, through the relief port 76.

While the primary piston 16 is further advanced, while the inner lip portion 206 of the cup seal 78 is in contact with the corner portion, the peak of the surface pressure is maintained at the position of the corner portion, and the relief port 76 The communication between the large diameter pressurization chamber 56 and the liquid supply chamber 71, that is, the reservoir 12, is continued, and finally, the cup seal 78 is loaded on the large diameter outer diameter portion 211 as a whole. The peak of the surface pressure moves to the protruding tip side of the inner lip portion 206 of the cup seal 78, whereby the large diameter pressurizing chamber 56 and the liquid supply chamber 71 through the relief port 76 are used. The interruption of communication with the reservoir 12 is continued.

Accordingly, the invalid stroke of the primary piston 16 until the large diameter pressurization chamber side blocking part 202 is in a closed state is such that the rear end of the cup seal 78 has a tapered outer diameter part 212 at the rear of the opening 76a. ), And shortens as indicated by D1 in FIG. Moreover, since the opening portion 76a of the relief port 76 is greatly opened in the initial position, high flow performance is also ensured.

Next, the small diameter hydraulic chamber side blocking part 201 will be described.

The small diameter piston part 46 of the primary piston 16 has a straight shape, and the relief port 58 opens the opening part 58a to the straight outer peripheral surface. And the cup seal 61 is provided in the initial part at the bottom part 15a side (left side in FIG. 2) rather than the opening part 58a as a whole.

Since the cup seal 61 moves on the outer circumferential surface of the same outer diameter, such a small diameter hydraulic chamber side blocking part 201 has a peak of surface pressure located on the bottom 15a side, that is, the front part of the cup seal 61. When the cup seal 61 exceeds the opening 58a of the relief port 58, the large diameter pressurizing chamber 56 and the primary side small diameter through the relief port 58 at the surface pressure peak portion, that is, the front portion The communication of the hydraulic chamber 49 is interrupted.

Accordingly, the invalid stroke of the primary piston 16 until the small diameter hydraulic chamber side blocking part 201 is closed is until the front portion of the cup seal 58 is located behind the opening 58a. , As shown by D2 in FIG. 2 (D2> D1). However, since the opening part 58a of the relief port 58 is largely opened without superposing | polymerizing to the cup seal 61 in the initial position, high flow performance is ensured.

Here, when the traction control device is combined with the discharge holes 113 and 114 of the master cylinder main body 11, the traction control device is the discharge hole 114 and the primary side small diameter hydraulic chamber 49. When the brake fluid is forcibly sucked from the reservoir 12 through the large diameter pressurizing chamber 56 and the liquid supply chamber 71, the opening 76a and the relief port 58 of the relief port 76 at an initial position are provided. Since the openings 58a are largely opened together, the brake fluid can flow to the traction control device at a large flow rate.

In addition, the secondary side breaker 200 also has the same configuration as the large diameter pressurization chamber breaker 202, thereby ensuring high flow performance.

And in 1st Embodiment, the small diameter hydraulic chamber communication port 82 which always communicates with the primary side small diameter hydraulic chamber 49 via the small diameter hydraulic chamber communication flow path 51 to the 1st member 21 is carried out. , A pressurization chamber communication port 83 which always communicates with the large-diameter pressurization chamber 56 via the pressurization chamber communication passage 59, and a liquid supply chamber communication port 84 which always communicates with the liquid supply chamber 71 are formed. These ports 82, 83 and 84 are connected to control valves 86 separate from the master cylinder body 11 via connecting flow paths 85a to 85c each formed of external piping.

The control valve 86 has a bottomed cylindrical valve cylinder body 87, a valve piston 88 fitted to slide in the valve cylinder body 87, and one end side of the valve piston 88. A valve spring 89 which presses the valve piston 88 in the direction of the bottom portion 87a of the valve cylinder body 87, closes the opening side of the valve cylinder body 87, and at the same time the valve piston 88 The cover member 90 which hold | maintains the valve spring 89 between them, and the C ring 91 which fixes the cover member 90 to the valve cylinder main body 87 are provided. Moreover, the valve cylinder 92 is comprised from the valve cylinder main body 87 and the cover member 90.

The valve piston 88 has a first shaft portion 93 formed on the tip side thereof, a second shaft portion 94 having a larger diameter is formed adjacent to the first shaft portion 93, and the second shaft portion 94 is formed. The third shaft portion 95 having a smaller diameter is formed adjacent to), and the fourth shaft portion 96 having a larger diameter than the second shaft portion 94 is formed adjacent to the third shaft portion 95. Thus, a fifth shaft portion 97 is formed adjacent to the fourth shaft portion 96 and inserted into the valve spring 89 at a smaller diameter. And the sealing member 99 is provided in the front-end | tip of the 1st shaft part 93. As shown in FIG. In addition, the second shaft portion 94 and the fourth shaft portion 96 of the valve piston 88 are two O-rings (ring seals) 100 and 101 which always seal a gap between the inner surface of the valve cylinder body 87. Is installed. In addition, two O-rings 100 and 101 may be provided on the valve cylinder body 87 side.

The bottom part 87a of the valve cylinder main body 87 is provided with the port 102 which opens and closes by the sealing member 99 of the valve piston 88, and this port 102 connects a flow path (large diameter pressurization chamber). And a pressure chamber communicating port 83 through a flow path communicated with 56]. Moreover, the 1st shaft part 93 which forms the outer peripheral side opposite to the valve cylinder body 87 and the valve spring 89 of the valve piston 88 in the bottom part 87a side of the side part 87b of the valve cylinder main body 87. ), A port 105 which is always in communication with the liquid chamber (relief chamber) 104 surrounded by the second shaft portion 94 and the seal member 100 is formed, and the port 105 is connected through the connection flow path 85c. It communicates with the liquid supply chamber communication port 84. Moreover, the valve cylinder main body 87, the 2nd shaft part 94 of the valve piston 88, the 3rd shaft part 95, the 4th shaft part 96, and the seal member are provided in the side part 87b of the valve cylinder main body 87. As shown in FIG. A port 107 is always in communication with the liquid chamber (the flow path through which the small-diameter hydraulic chamber 49 and the valve cylinder 92 communicate) surrounded by the 100 and the seal member 101, and the port (107) is formed. 107 communicates with the small diameter hydraulic chamber communication port 82 via a connection flow path (the flow path where the small diameter hydraulic chamber 49 and the valve cylinder 92 communicate) 85a. Here, the sealing member 99 of the valve piston 88 and the port 102 of the valve cylinder body 87 communicate between the connection passage 85b communicated with the liquid chamber 104 and the large diameter pressurization chamber 56. The opening / closing valve mechanism 108 is configured to shut off.

And the control valve 86 is a valve piston 88 of the hydraulic pressure of the large diameter pressurization chamber 56 introduced into the port 102 and the primary side small diameter hydraulic chamber 49 introduced into the liquid chamber 106. The balance is achieved by the hydraulic pressure and the pressing force of the valve spring 89. The balance at this time is represented by the following equation.

That is, as shown in Fig. 4, the seal cross-sectional area by the O-ring 101 is A1, and the seal cross-sectional area by the O-ring 100 is A2 (where A2 < A1) and the seal cross-sectional area by the sealing member 99. When A3 is set, the hydraulic pressure of the primary-side small diameter hydraulic chamber 49 is Pa, the hydraulic pressure of the large diameter pressure chamber 56 is Pb, and the set load of the valve spring 89 is F.

Pa × (A1-A2) + Pb × A3 = F

Becomes

And, as shown in FIG. 5, when the hydraulic pressure of the large diameter pressurization chamber 56 starts to rise (p1 point), the primary side small diameter hydraulic chamber 49 also opens the cup seal 61 by the said cup seal 61. It rises with the hydraulic pressure and dynamic pressure of the diameter pressurization chamber 56 (p1-p2 point). Then, if Pa x (A1-A2) + Pb x A3> F (p2 point. The hydraulic pressure at this point is called the pressurization chamber release hydraulic pressure), the valve piston 88 of the control valve 86 is the valve spring 89. The port 102 is opened slightly to counteract the pressing force of), and the hydraulic pressure release of the large diameter pressurization chamber 56 is started. At this time, as the hydraulic pressure Pa of the primary-side small diameter hydraulic chamber 49 rises so as to satisfy the formula of Pa × (A1-A2) + Pb × A3 = F, the large diameter pressurization chamber 56 In other words, the large diameter so that the hydraulic pressure Pb of the large diameter pressurization chamber 56 falls in accordance with the following formula so that the hydraulic pressure Pb may fall. The hydraulic pressure Pb of the pressure chamber 56 is pushed out to the reservoir 12 side through the liquid replenishing chamber 71 (p2 points to p3 points).

Pb = {F-Pa × (A1-A2)} ÷ A3

Here, at the time of high boost, that is, when the brake pedal is pressed at a relatively high speed, the input from the brake booster increases linearly, and the hydraulic pressure Pa of the primary-side small diameter hydraulic chamber 49 is at a constant ratio. Since it rises, the control valve 86 is pushed to the reservoir 12 side so that it may gradually fall along the gradient which set the hydraulic pressure Pb of the large diameter pressurization chamber 56. As shown in FIG. This gradient can be arbitrarily set by appropriately selecting the seal cross-sectional areas A1 to A3 and the like and can be tuned to the vehicle.

And the balance diet,

Pa × (A1-A2)> F

In this case, since the control valve 86 is kept open, the hydraulic pressure in the large diameter pressurization chamber 56 is released and becomes atmospheric pressure (after p3 point), and the brake hydraulic pressure is maintained only by the primary side small diameter hydraulic chamber 49. To control.

Next, the operation of the master cylinder of the first embodiment will be described.

When the primary piston 16 is pressed in the direction of the bottom portion 15a by the rod of the booster connected to the brake pedal, the secondary piston 17 also moves simultaneously through the primary piston spring 68. On the primary piston 16 side, the large diameter pressurization chamber side breaker 202 having a short invalid stroke closes the relief port 76 by the cup seal 78, and then the large diameter pressurization chamber 56 is closed. This hydraulic pressure is raised to supply liquid to the primary side small diameter hydraulic chamber 49 via the cup seal 61. At this time, even if the small diameter hydraulic chamber side blocking part 201 having an invalid stroke is not closed, the liquid flows from the large diameter pressurizing chamber 56 side to the primary side small diameter hydraulic chamber 49 side. Only through 201), there is no problem because it is the same as the liquid supply by the cup seal 61. The secondary side small diameter hydraulic chamber 32 raises the hydraulic pressure also when the relief port 35 of the secondary side breaker 200 is closed by the cup seal 36 with respect to the secondary piston 17.

Then, when the hydraulic pressure rises, the stroke amount of the primary piston 16 x [the outer diameter-primary side small diameter hydraulic pressure chamber 49 of the large diameter pressurization chamber 56 is about the primary side small diameter hydraulic pressure chamber 49. Outside diameter] of the liquid is pushed open the cup seal 61 from the large diameter pressurization chamber 56 to the primary side small diameter hydraulic chamber 49, and the invalid liquid amount (mainly caliper rollback) at the beginning of the stroke. Replenish Thereafter, in order to compensate for the lack of liquid amount associated with the small diameter of the primary-side small diameter hydraulic chamber 49, the brake fluid is sent from the large-diameter pressure chamber 56 to the primary-side small diameter hydraulic chamber 49. The large diameter pressurization chamber 56 and the primary side small diameter hydraulic chamber 49 rise up to the pressure chamber release hydraulic pressure at the same pressure (p1 to p2 points).

Then, when the pressure rises to the pressure release chamber hydraulic pressure, the control valve 86 releases the pressure of the large diameter pressurization chamber 56. At this time, the control valve 86 is large so that the hydraulic pressure Pb of the large diameter pressurization chamber 56 gradually lowers as the hydraulic pressure Pa of the primary side small diameter hydraulic chamber 49 rises as described above. The hydraulic pressure Pb of the diameter pressurization chamber 56 is pushed toward the reservoir 12 side through the liquid supply chamber 71 (p2 point to p3 point).

Then, when the hydraulic pressure of the large diameter pressurization chamber 56 is released and reaches atmospheric pressure, the control valve 86 is kept open, and the brake hydraulic pressure is controlled only by the primary side small diameter hydraulic chamber 49.

According to 1st Embodiment demonstrated above, the hydraulic pressure of the large diameter pressurization chamber 56 once raised is pushed to the reservoir 12 side so that it may gradually reduce with the hydraulic pressure rise of the primary side small diameter hydraulic chamber 49. It is possible to reduce the volume of the large diameter pressurizing chamber 56 due to the sliding movement toward the primary side small diameter hydraulic chamber 49 side of the stepped primary piston 16 because it has a control valve 86 which can be used. By opening the cup seal 61, the liquid is supplied from the large diameter pressurization chamber 56 side to the primary side small diameter hydraulic chamber 49 side, that is, first peeling to increase the hydraulic pressure of the large diameter pressurization chamber 56. The lower surface control valve 86 pushes the hydraulic pressure of the large diameter pressurization chamber 56 to the reservoir 12 so as to gradually lower the hydraulic pressure of the primary side small diameter hydraulic chamber 49 as the hydraulic pressure increases.

Therefore, the pedal stroke can be shortened by the effect of the first peel, and when the hydraulic pressure of the large diameter pressurization chamber 56 is released, the hydraulic pressure of the large diameter pressurization chamber 56 gradually decreases without dropping at once. The pedal reaction force does not go down at once, and the pedal stroke is elongated without accompanying the pedal effort, and the movement to the primary side small diameter hydraulic chamber 49 side is prevented. As a result, it feels as if it is lightly stepped off. It can reduce the discomfort on pedal peeling by reducing only the vehicle speed.

That is, as shown in Fig. 6, in view of the characteristics of the hydraulic pressure rise with respect to the pedal stroke, the first embodiment includes a large diameter pressurizing chamber 56 having a large diameter and a shortening stroke with respect to a straight type master cylinder. By using a combination of the primary side small diameter hydraulic chamber 49 having a small diameter and the stroke extending with respect to the straight type master cylinder, as a result, when the straight type is set as shown by X1 in FIG. 6 ( It is possible to shorten the pedal stroke required to generate the same hydraulic pressure with respect to X2 in FIG. 6).

Here, X3 in FIG. 6 denotes the characteristic of the straight type only for the large diameter pressurization chamber 56, and X4 in FIG. 6 represents the straight type of the primary side small diameter hydraulic chamber 49 only. The characteristics of, respectively, A represents the shortening amount of the pedal stroke of the master cylinder (X1) of the first embodiment with respect to the master cylinder (X2) when set to the straight type, B is a straight only of small diameter The shortening amount of the pedal stroke with respect to the master cylinder X4 in the case of type is shown, respectively.

In Fig. 7 showing the relationship between the pedal effort and the hydraulic pressure rise, the line LP represents the relationship between the pedal effort and the hydraulic pressure increase in the large diameter pressurization chamber 56, and the line SP is the primary side small diameter. Although the relationship between the pedal effort and the hydraulic pressure rise in the hydraulic chamber 49 is shown, respectively, the conventional master cylinder has the hydraulic pressure of the large diameter pressurization chamber 56 at a time when the hydraulic pressure of the large diameter pressurization chamber 56 is released. By descending, as shown by Y1 in Fig. 7A, the hydraulic pressure rises without accompanying the pedal effort. In the master cylinder of the first embodiment, the control valve 86 is provided to provide a large diameter pressurization chamber. Since the hydraulic pressure of 56 decreases gradually, the pedal reaction force does not drop at once, and as shown by Y2 in FIG. 7B, the pedal effort accompanies and the hydraulic pressure rises. By feeling This can reduce the discomfort on the pedal filling of the vehicle speed only. In Fig. 7, R is a middle line between the line LP and the line SP, and is intended to make it easier to compare the line LP and the line SP.

In addition, since it is used in the same manner as the master cylinder when the pedal ratio is set to the straight type, it is possible to improve the generated hydraulic pressure by the pedal ratio for the long stroke type master cylinder of the same size as the small diameter.

In addition, the primary piston until the small diameter hydraulic chamber side blocking part 201 is in the closed state, and the primary piston 16 until the large diameter pressurizing chamber side blocking part 202 is in the closed state, is the primary piston. Since it is long with respect to the invalid stroke of (16), only about managing the axial position accuracy of the large diameter pressurization chamber side block part 202 about the shortening of the invalid stroke for early realizing a first fill performance as a master cylinder. Also, it is unnecessary to strictly control the positional accuracy in the axial direction with respect to the small-diameter hydraulic chamber side breaker 201. And even in this way, at the time of liquid replenishment from the large diameter pressurization chamber 56 to the primary side small diameter hydraulic chamber 49, the small diameter hydraulic chamber side blocking part 201 with a long invalid stroke will be in a closed state. Even if not, when the large diameter pressurization chamber side interruption | blocking part 202 with a short invalid stroke is closed, the large diameter pressurization chamber by sliding of the primary piston 16 to the primary side small diameter hydraulic chamber 49 side will be closed. The flow of brake fluid generated by the volume reduction of 56 is from the large diameter pressurizing chamber 56 side through the small diameter hydraulic chamber side blocking part 201 to the primary side small diameter hydraulic chamber 49 side, and the cup seal ( Since it becomes the same flow as liquid replenishment from the large diameter pressurization chamber 56 side through 61) to the primary side small diameter hydraulic chamber 49 side, the first peel performance is not reduced.

Furthermore, since liquid supply from the large diameter pressurization chamber 56 at the initial stage of operation to the primary side small diameter hydraulic chamber 49 can be performed without passing through the small diameter hydraulic chamber side blocking section 201, the liquid flow resistance This does not occur, and the first peel performance is improved.

Therefore, since the performance of the first fill and the performance of the high flow can be secured, since a low cost type blocking structure can be adopted for one small diameter hydraulic chamber side breaker 201, the cost can be reduced.

In addition, the first embodiment described so far may be changed as follows.

As shown in FIGS. 8 and 9, the hole-shaped relief port 76 formed in the primary piston 16 is stopped, and the bottom portion 15a is larger than the tapered outer diameter portion 212 of the large diameter piston portion 47. On the) side (left side in FIG. 8), a plurality of straight groove portions 215 penetrating to the bottom part 15a side along the axial direction are provided in the circumferential direction (for example, at a position that divides the circumference into 36 equal parts), The port 74 and the large diameter pressurizing chamber 56 can be communicated through the groove portion 215.

Then, when the primary piston 16 is in the initial position, the cup seal 78, which does not contact the tapered outer diameter portion 212, opens the port 74 and the large diameter pressurizing chamber 56 through the groove portion 215. When the primary piston 16 slides toward the primary side small diameter hydraulic chamber 49 and the cup seal 78 is mounted on the tapered outer diameter portion 212, the cup seal 78 is formed in the groove portion 215. It is to block the communication between the port 74 and the large diameter pressurization chamber 56 through. In this case, the passage cross-sectional area of the gap between all the grooves 215 and the cup seals 78 is equal to or larger than φ4 (mm). Here, the groove portion 215 may be either a U-shaped groove or a square groove in addition to the V-shaped groove shown in FIG. 9. In the case where the groove portion 215 is formed by rolling, the dimensional accuracy thereof is not very good. However, in order to improve the dimensional accuracy, the rear end of the groove portion 215 has an annular V-shaped groove ( 216 is formed. By this V-groove 216, the tight tolerance with respect to an invalid stroke can be responded to.

The above configuration eliminates the necessity of forming a complicated port, and the groove portion 215 can be easily formed by rolling or forging, so that the processing time can be shortened and the cost accompanying it can be reduced. In addition, by deepening the depth of the groove portion 215, the cross-sectional area of the flow path can be easily enlarged, which is effective in improving the high flow performance.

Moreover, in the master cylinder of 1st Embodiment mentioned above, although the case where the control valve 86 was separately provided with respect to the master cylinder main body 11 was demonstrated as an example, as shown in FIG. 10, the master cylinder main body 11 was shown. For example, it is also possible to integrally install the control valve 86 together with the connecting pipe bodies 85a to 85c in the first member 21. In this case, the axes of the valve piston 88 of the control valve 86 are arranged in parallel and in the axial direction with respect to the primary piston 16 and the secondary piston 17 which are coaxially arranged. The increase in the axial length is prevented.

Moreover, in the master cylinder of 1st Embodiment mentioned above, the inside of the step-type cylinder 15 was made into the large diameter pressurization chamber 56 of the large diameter piston part 47 side, and the primary side of the small diameter piston part 46 side. An example is provided in which the cup seal 61 is partitioned into the small diameter hydraulic chamber 49 and only the flow of the brake fluid from the large diameter pressure chamber 56 to the primary side small diameter hydraulic chamber 49 is provided. However, it is not limited to this, Instead of the cup seal 61, you may provide the sealing check valve (return opening / closing part).

Next, the master cylinder of 2nd Embodiment of this invention is demonstrated mainly with reference to FIG. 11 centering on a different part from 1st Embodiment. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the description is abbreviate | omitted.

In the master cylinder of 2nd Embodiment, the structure of the control valve 86 differs with respect to 1st Embodiment. That is, one end side of the valve piston 88 of the control valve 86 of the second embodiment is opened to the outer diameter side of the first shaft portion 93, that is, the liquid chamber 104, and the other end side thereof is the fifth shaft portion 97. An throttling passage 110 is opened to an end surface of the cavities.

Moreover, the cover member 90 of the control valve 86 of 2nd Embodiment is screwed to the valve cylinder main body 87, The O-ring (ring seal) 111 which seals these clearances is provided between these. Is installed. As a result, the valve spring 89 is disposed between the valve cylinder 92 and the liquid chamber 104 of the valve piston 88 to form a damper chamber 112 in which hydraulic pressure acts. The damper chamber 112 communicates with the liquid chamber 104 via the throttle passage 110 (in other words, the damper chamber 112 has the other end side opposite to the liquid chamber 104 in the damper chamber 112). Open].

Next, the operation of the master cylinder of the second embodiment will be described.

When the primary piston 16 is pressed in the direction of the bottom portion 15a by the rod of the booster connected to the brake pedal, the large diameter pressurization chamber 56 and the primary side small diameter hydraulic chamber 49 rise to the pressure chamber release hydraulic pressure. The same operation as in the first embodiment is performed until the time is set (p1 to p2 points shown in FIG. 5).

Then, when the pressure rises to the pressure release chamber hydraulic pressure, the control valve 86 releases the pressure of the large diameter pressurization chamber 56. At this time, the control valve 86 is substantially the same as the first embodiment in accordance with the increase in the hydraulic pressure Pa of the primary-side small diameter hydraulic chamber 49, and the hydraulic pressure Pb of the large diameter pressurization chamber 56 gradually. To this end, the hydraulic pressure Pb of the large diameter pressurization chamber 56 is pushed toward the reservoir 12 side through the liquid supply chamber 71 (p2 to p3 points shown in FIG. 5).

In the meantime, the valve piston 88 micro-opens and closes the port 102 by micro oscillation at high speed, and the liquid chamber 104 receives the hydraulic pressure Pb of the large diameter pressurization chamber 56 introduced through the connection flow path 85b. Although it pushes toward the reservoir 12 side through the connection flow path 85c and further the liquid supply chamber 71, the damper chamber 112 and the liquid chamber 104 communicate with each other through the throttle passage 110, When the piston 88 vibrates minutely at a high speed, the volume of the damper chamber 112 is repeatedly increased and decreased, and as a result, the brake fluid between the damper chamber 112 and the liquid chamber 104 through the throttle passage 110. This is done back and forth, so that the throttle passage 110 becomes a liquid flow resistance to obtain a damper effect. As a result, the high speed micro vibration of the valve piston 88 is attenuated, and generation | occurrence | production of the noise by the high speed micro vibration of the valve piston 88 can be prevented.

In addition, the liquid flow resistance generated by the throttle passage 110 is such that it does not hinder operation at a normal operating speed, and is set to such an extent that it cannot cope with the high-speed micro-vibration that causes the valve piston 88 to generate a joint. As a result, the high speed small vibration of the valve piston 88 is attenuated.

Then, when the hydraulic pressure in the large diameter pressurization chamber 56 is released and reaches atmospheric pressure, the control valve 86 is kept open as in the first embodiment, and the brake hydraulic pressure is applied only by the primary side small diameter hydraulic chamber 49. Control.

In addition, in any of the above embodiments, the relief chamber of the control valve communicates with the reservoir, and the brake fluid when the hydraulic pressure of the large diameter pressurization chamber is released is returned to the reservoir from the relief chamber, but is not limited thereto. For example, an accumulator for accommodating brake fluid may be provided so that the relief chamber communicates with the accumulator so that the brake fluid when the hydraulic pressure of the large diameter pressurization chamber is released may be accumulated in the accumulator through the relief chamber.

As explained above, according to the master cylinder of this invention, since it has a control valve which can gradually reduce the hydraulic pressure of a large diameter pressurization chamber with the increase of the hydraulic pressure of a small diameter hydraulic chamber, the small diameter hydraulic chamber side of a stepped piston When the large diameter pressurization chamber is reduced by the volume reduction of the large diameter pressurization chamber, the check opening and closing part is opened, and liquid is supplied from the large diameter pressurization chamber side to the small diameter hydraulic chamber side, that is, the first fill is performed, The control valve gradually lowers the hydraulic pressure in the large diameter pressure chamber as the hydraulic pressure increases in the small diameter hydraulic chamber.

Therefore, the pedal stroke can be shortened by the effect of the first peel, and when the hydraulic pressure of the large diameter pressurizing chamber is released, the hydraulic pressure of the large diameter pressurizing chamber decreases gradually without dropping at once. Without this, the pedal stroke is prevented from extending and moving to the small-diameter hydraulic chamber side without the pedal effort, and as a result, it is possible to reduce the discomfort on the pedal peeling of the vehicle in which only the vehicle speed is reduced as if it is lightly stepped off. .

In addition, when the damper chamber and the relief chamber communicate with each other through the throttle passage formed in the valve piston, the valve piston of the open / close valve mechanism pushes the hydraulic pressure of the large diameter pressurization chamber toward the reservoir so as to gradually decrease the hydraulic pressure of the small diameter hydraulic chamber. When the micro oscillation is performed at high speed, the volume of the damper chamber repeatedly increases and decreases. As a result, the brake fluid flows between the damper chamber and the relief chamber through the throttle passage, and the throttle passage becomes a liquid flow resistance, thereby reducing the damper effect. You can get it. Therefore, the microvibration of the valve piston is attenuated, and generation of a joint due to the high speed microvibration of the valve piston can be prevented.

Moreover, according to the master cylinder of this invention, the invalid stroke of the stepped piston until the small diameter hydraulic chamber side blocking part is closed, and the invalid stroke of the stepped piston until the large diameter pressurization chamber side blocking part is closed. Since it is long relative to, for the shortening of the invalid stroke for early realizing the first fill performance as the master cylinder, it is only necessary to manage the axial position accuracy of the large diameter pressurization chamber disconnection part. It is unnecessary to strictly control the positional accuracy in the axial direction with respect to the part.

In this way, when the liquid is supplied from the large diameter pressurizing chamber to the small diameter hydraulic chamber, even if the small diameter hydraulic chamber side blocking part with the long invalid stroke is not closed, the large diameter pressurization chamber side blocking part with the short invalid stroke is closed. The flow of the brake fluid caused by the volume reduction of the large diameter pressurization chamber due to the sliding movement of the stepped piston to the small diameter hydraulic chamber side passes through the small diameter hydraulic chamber side shutoff portion. Since the flow is the same as that of the liquid supply from the large diameter pressurization chamber side through the check opening / closing portion to the small diameter hydraulic chamber side, the first peel performance is not deteriorated.

Moreover, since liquid replenishment from the large diameter pressurization chamber to the small diameter hydraulic chamber at the initial stage of operation can be made without going through the check opening / closing portion, no liquid flow resistance occurs and the first fill performance is further improved.

Therefore, since the first fill performance and the high flow performance can be secured, a low cost type blocking structure can be adopted on the one hand, thereby reducing the cost.

Moreover, since it is not influenced by the boosting speed by the pedal, it is possible to stably perform the first peel in any boosting operation.

BRIEF DESCRIPTION OF THE DRAWINGS The side cross section which shows the structure of the master cylinder of 1st Embodiment of this invention.

FIG. 2 is a detailed view of portion A of FIG. 1 of the master cylinder of the first embodiment of the present invention. FIG.

FIG. 3 is a detailed view of portion B of FIG. 1 of the master cylinder of the first embodiment of the present invention. FIG.

It is sectional drawing which shows the cross-sectional area of the seal part of the valve piston of the control valve of the master cylinder of 1st embodiment of this invention.

Fig. 5 is a characteristic diagram showing the relationship between the hydraulic pressure of the primary side small diameter hydraulic chamber of the master cylinder of the first embodiment of the present invention and the hydraulic pressure of the large diameter pressurizing chamber.

Fig. 6 is a characteristic diagram showing a relationship between a pedal stroke and a hydraulic pressure of a master cylinder according to the first embodiment of the present invention.

Fig. 7 is a characteristic diagram showing the relationship between the pedal effort and the hydraulic pressure of a conventional master cylinder, and a characteristic diagram showing the relationship between the pedal effort and the hydraulic pressure of the master cylinder according to the first embodiment of the present invention.

8 is a partial cross-sectional view of a primary piston of a modification of the master cylinder of the first embodiment of the present invention.

Fig. 9 is a C arrow view of Fig. 8 of a modification of the master cylinder of the first embodiment of the present invention.

10 is a cross-sectional view of a plurality of cross sections of a modification of the configuration of the master cylinder of the first embodiment of the present invention.

11 is a cross-sectional view showing a control valve of the master cylinder according to the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

11: master cylinder body

12: reservoir

15: stepped cylinder

16: primary piston (stepped piston)

40: small diameter cylinder

41: large diameter cylinder

46: small diameter piston

47: large diameter piston

49: primary side small diameter hydraulic chamber (small diameter hydraulic chamber)

56: large diameter pressure chamber

61: cup seal (the check opening part)

85a: Connection flow path (flow path where the small diameter hydraulic chamber and the valve cylinder communicate)

85b: Connecting flow passage (flow passage communicating with large diameter pressurization chamber)

86: control valve

88: valve piston

89: valve spring

92: valve cylinder

100, 101: O ring (ring seal)

104: liquid chamber (relief chamber)

106: liquid chamber (flow path through which the small diameter hydraulic chamber and the valve cylinder is in communication)

108: on-off valve mechanism

110: throttle passage

112: damper chamber

201: small diameter hydraulic chamber breaker

202: large diameter pressurization measurement breaker

Claims (7)

A stepped cylinder having a large diameter cylinder portion and a small diameter cylinder portion, A stepped piston having a large diameter piston portion slidably inserted into the large diameter cylinder portion of the stepped cylinder and a small diameter piston portion slidably inserted into the small diameter cylinder portion; A check valve that divides the stepped cylinder into a large diameter pressurizing chamber on the large diameter piston part side and a small diameter hydraulic chamber on the small diameter piston part side, and allows only a flow of brake fluid from the large diameter pressurizing chamber side to the small diameter hydraulic chamber side. With opening and closing part, Wherein the check opening / closing part is opened by a decrease in the volume of the large diameter pressurizing chamber by sliding the stepped piston toward the small diameter hydraulic chamber side to supply liquid from the large diameter pressurizing chamber side to the small diameter hydraulic chamber side. As a master cylinder, And a control valve which gradually lowers the hydraulic pressure of the large diameter pressure chamber as the hydraulic pressure rises in the small diameter hydraulic chamber. The valve according to claim 1, wherein the control valve has a valve piston and a valve spring for urging the valve piston in the valve cylinder, and the valve piston has a driving force generated by the hydraulic pressure of the small diameter hydraulic chamber and the hydraulic pressure of the large diameter pressure chamber. A master cylinder, characterized in that to reduce the hydraulic pressure of the large diameter pressurizing chamber when the force added to the thrust force generated by the pressure exceeds the pressing force by the valve spring. The valve of claim 2, wherein the master cylinder includes a reservoir for storing brake fluid, and the control valve is provided with at least two ring seals between the valve cylinder and the valve piston so as to partition the inside of the valve cylinder. A seal formed between the seal and the small diameter hydraulic chamber communicate with each other, the valve spring is provided on one end of the valve piston, and the reservoir and the large diameter pressurization chamber communicate with the other end of the valve piston. A master cylinder, comprising: a relief chamber provided with an on-off valve mechanism for communicating and disconnecting the relief chamber from the large diameter pressurization chamber. The said at least two ring seal is provided in the said valve piston, The diameter of the ring seal provided in the valve spring side is larger diameter than the diameter of the ring seal provided in the relief chamber side. To master cylinder. The valve cylinder according to claim 3, wherein the valve cylinder is divided into two chambers formed by two ring seals, a chamber formed between the relief chamber and the ring seal, and a damper chamber in which the valve spring is accommodated. A master cylinder which is open to the relief chamber and has a throttle passage opening at the other end to the damper chamber. The reservoir according to any one of claims 1 to 5, wherein the reservoir stores the brake fluid; A large diameter pressurization chamber side blocking unit which is closed by sliding of the stepped piston toward the small diameter hydraulic chamber side and blocks communication between the large diameter pressurizing chamber and the reservoir; It is further provided with a small diameter hydraulic chamber side blocker which is closed by sliding of the stepped piston toward the small diameter hydraulic chamber side and blocks communication between the large diameter pressure chamber and the small diameter hydraulic chamber, The invalid stroke of the stepped piston until the small diameter hydraulic chamber side blocking part is closed is longer than the invalid stroke of the stepped piston until the large diameter pressurizing chamber side blocking part is closed. Master cylinder characterized by the above. Reservoir for storing brake fluid, A stepped cylinder having a large diameter cylinder portion and a small diameter cylinder portion, A stepped piston having a large diameter piston portion slidably inserted into the large diameter cylinder portion of the stepped cylinder and a small diameter piston portion slidably inserted into the small diameter cylinder portion; A check valve that divides the stepped cylinder into a large diameter pressurizing chamber on the large diameter piston part side and a small diameter hydraulic chamber on the small diameter piston part side, and allows only a flow of brake fluid from the large diameter pressurizing chamber side to the small diameter hydraulic chamber side. With the opening and closing part, A large diameter pressurization chamber side blocking unit which is closed by sliding of the stepped piston toward the small diameter hydraulic chamber side and blocks communication between the large diameter pressurizing chamber and the reservoir; A small diameter hydraulic chamber side blocking portion which is closed by sliding of the stepped piston to the small diameter hydraulic chamber side to block communication between the large diameter pressure chamber and the small diameter hydraulic chamber, A master cylinder for supplying liquid from the large diameter pressure chamber side to the small diameter hydraulic chamber side by opening the check opening / closing portion by volume reduction of the large diameter pressurization chamber due to sliding of the stepped piston to the small diameter hydraulic chamber side. as, The invalid stroke of the stepped piston until the small diameter hydraulic chamber side blocking part is closed is longer than the invalid stroke of the stepped piston until the large diameter pressurizing room side blocking part is closed. Master cylinder characterized by the above.